A contactor is a switch that is located in the outdoor part of the air conditioning unit that controls the flow of electricity to components in the AC unit.
There are no other terms for this part.
The switch turns the unit on and off as required to keep the home at the desired temperature.
There is only one type of contractor used for your air conditioning unit.
The air conditioner contactor can fail either electrically or mechanically.
Mechanical issues: The contactor can stick closed which can be noticed if your condensing unit (the unit located outside) will not shut off after turning off your thermostat. It’s common to find ice covering the refrigerant line and evaporator coil when this happens. If the contractor is sticking, it should be replaced.
The contractor can fail to mechanically close if something has gotten into the mechanism to physically prevent it from closing. This usually is caused by insects or mice.
Electrical issues: Excess current flowing through the contacts can cause them to melt. Age, hot temperatures, power quality, mechanical shock, excessive vibration or a corrosive environment can be contributing factors to electrical issues with your contractor.
We will replace the broken contactor with a new one. For your safety, we don’t recommend replacing the contactor on your own because it’s an electrical component and can cause electrocution.
Even if your contractor is working, it pays to replace it every five years or so.